Ubiquitin-positive pneumocytes are present in non-specific interstitial pneumonia with immunohistochemical analyses

Pneumocyte injury and ubiquitin-positive pneumocytes in interstitial lung diseases

Pneumocyte injury is a characteristic of pulmonary interstitial pneumonias (IPs). Histological markers of pneumocyte injury and inflammation include pneumocyte necrosis, erosion, hyaline membrane and fibrin exudation with subsequent intraluminal granulation tissue formation. We found that intracytoplasmic inclusions in pneumocytes are ubiquitin-positive (Ub⁺) and that the number of Ub⁺ pneumocytes shows positive correlation with the extent of diffuse alveolar damage (DAD). To determine the role of Ub⁺ pneumocytes and inclusions in IPs, we studied their relationship with pathological and clinical features of DAD, usual interstitial pneumonia (UIP) and organizing pneumonia (OP), including airspace enlargement with fibrosis (AEF). We analysed Ub⁺ pneumocytes, inclusions, erosions and intraluminal granulation tissue in relation to pneumocyte injury. The numbers of immunohistochemically identified Ub⁺ inclusions in each IP were higher than the number of inclusions detected by light microscopy. The inclusions detected by Ub⁺ immunostaining were identical to the inclusions observed by light microscopy. UIP and DAD had many Ub⁺ inclusions, while OP and AEF had fewer Ub⁺ inclusions. These results suggest that the extent of Ub⁺ inclusions reflects the severity of pneumocyte injury among IPs. Thus, Ub⁺ inclusions are a histological marker of pneumocyte injury that may be helpful in determining the severity and prognosis of IPs.

Airspace enlargement with fibrosis shows characteristic histology and immunohistology different from usual interstitial pneumonia, nonspecific interstitial pneumonia and centrilobular emphysema

The histologic characteristics of air space enlargement with fibrosis (AEF) are compared with usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP) and centrilobular emphysema (CLE) to determine similarities and differences. Lung specimens from 39 patients were studied; 9 with AEF, 13 with UIP and 5 with CLE identified in lobectomy specimens for cancer and 12 NSIP cases identified on surgical lung biopsies. We determined the characteristics of cystic structures (i.e. abnormal airspace), degree of inflammation and severity of pneumocyte injury semi-quantitatively. In AEF, the wall thickness of the cystic lesions (0.8 mm) was thinner than in UIP (2.1 mm) and thicker than in CLE (0.07 mm). The degree of inflammation and granulation tissue were milder in AEF than in UIP and NSIP and CLE showed milder inflammatory cells than AEF. As for pneumocyte injury, AEF had fewer erosions (0.1/case) and fewer ubiquitin-positive pneumocytes than UIP (4.8 cells/slide) and NSIP (9.8 cells/slide). Our data suggested that the histological characteristics of AEF differed significantly from UIP, NSIP and CLE.

Morphological data indicate a stress response at the oral border of strangulated small intestine in horses

Strangulation colic often leads to surgery. We aimed to document the molecular response in the non-resected intestine in these horses using quantitative Western blot analysis, and immunohistochemistry. The expression of hypoxia-inducible factor 1-alpha (HIF1α) was investigated together with two molecular pathways initiated after protein destruction: proteasome degradation via ubiquitin chain formation and protein restoration via molecular chaperones such as inducible heat shock protein 70 (HSP70). In addition, the expression of c-fos and c-jun could indicate an early proinflammatory response. Ubiquitin, HSP70, c-jun and c-fos protein levels did not differ between the control and colic samples nor were they related to the clinical outcome in case of strangulation colic. However, the immunohistochemical distribution of several of these proteins (ubiquitin, HSP70 and c-jun) differed significantly between colic and control samples. The elevated presence of ubiquitin in the enterocytes' nucleus, of HSP70 in the smooth muscle cells' nucleus and of c-jun in enteric neurons suggest protective and degenerative pathways are activated in the apparently healthy non-resected tissue in case of strangulation obstruction, perhaps providing a molecular and morphological basis for the development of complications like post-operative ileus.

Ubiquitin-positive pneumocytes and inclusion bodies are present in secondary organizing pneumonia

OBJECTIVE

We previously reported that various types of interstitial pneumonia (IP) patterns contain intracytoplasmic eosinophilic inclusions or Mallory bodies (inclusions) that are ubiquitin positive (Ub+). In the present study, we examined tissues with the organizing pneumonia pattern (OP) to determine if they contain inclusions and Ub+ pneumocytes using lobectomized specimens.

METHODS

Tissues from 34 patients with secondary OP, which appeared in 33 carcinomas and 1 pulmonary abscess, were histologically evaluated for the type of intraluminal granulation tissue and the presence of erosions and inclusions. Granulation tissues were classified into polypoid, mural and occluded subtypes according to Basset's criteria and scored.

RESULTS

Inclusions were noted in 5.9% of the secondary OP cases with light microscope. Ub+ pneumocytes were detected after immunostaining and all inclusions were Ub+. Ub+ pneumocytes (inclusions) were noted in 14.7% of the secondary OP cases. OP contained pneumocyte erosions and inflammatory cell infiltration without a significant difference in the Ub+ and Ub- subgroups. Although there was no significant difference in the polypoid type of granulation tissue between the Ub+ and Ub- negative (Ub-) subgroups, the Ub+ subgroup had significant increases (p<0.05) in the mural-occluded type of granulation tissue (Ub+: 1.76±0.64, n=5 vs. Ub-: 0.72±0.87, n=29) as compared to the Ub- subgroup.

CONCLUSION

Some patients with secondary OP had Ub+ inclusions as pneumocyte injury.

[Immunohistochemical study of nonspecific interstitial pneumonia and ubiquitin-positive pneumocytes in elderly patients]

AIM

The Ubiquitin (Ub)-proteasome system maintains cellular homeostasis through proteolysis, and Ub appears in the damaged cells of many organs. Nonspecific interstitial pneumonia (NSIP)in elderly patients was studied to clarify the relationship between Ub-positive cells, cellular damage, and resistance to therapy.

METHODS

Specimens of surgical lung biopsy with the NSIP pattern (NSIP/P) from 13 patients (mean age, 68 years old) were examined histologically and immunohistochemically. Pneumocytes examined under high-power microscopy were counted for eosinophilic inclusion bodies and Ub-positive cells. NSIP/P was histologically evaluated and cases were scored for erosion and intraluminal granulation tissue subtypes (polypoid, mural, or occluded) as lung injury markers. NSIP/P was subdivided into cellular NSIP and fibrosing NSIP according to the proportions of interstitial inflammation and fibrosis.

RESULTS

1) Six of 13 patients with NSIP/P had Ub-positive cells (Ub+ group), and all inclusions identified by light-microscope were positive for Ub. A greater number of Ub+ pneumocytes were found compared with the inclusions by light-microscope, and Ub immunostaining was useful for the detection of the inclusions. 2) Granulation tissue scores in the Ub+ group were significantly greater than in the Ub- group (p<0.05); there was no difference in granulation tissue subtypes between the groups. 3) Granulation tissue scores in fibrosing NSIP/P (including each subtype) were significantly greater than in cellular NSIP/P. 4) After a follow-up period, there was no correlation between Ub+ group and NSIP therapy resistance or between the granulation tissue subtypes and therapy resistance.

CONCLUSION

Some elderly patients with NSIP had inclusions, and these inclusions were Ub+. Pneumocyte injury might occur via the Ub-proteasome system pathway in elderly patients with NSIP/P, although there was no correlation between Ub+ pneumocytes and therapy resistance.